Sphere, tubes, wedges and boxes may make for the perfect warship but how many people do you know will want to use them in their game?
Well, there's me. In my mind, if a spaceship is a beautiful woman, then the warship is the mother-in-law with the big rolling pin in one hand: you know at a glance that you really don't want to mess with her.
I’m going to try and explain my philosophy on space combat. ... a reporter asks the Captain what is the defense against Nuclear Torpedoes. His basic answer: None.
Fast forward to the 90’s, missiles like the non-nuclear Harpoon devastate ships and torpedoes explode under the ship’s keel to crack the back of ships. ...
Now advance this line of thought several centuries into the future ... Explosives would have advanced as well delivering more and more destructive force at the point of impact. No matter how much armor technology advances there will always be a way to defeat it using conventional means.
... it’s easier for an invading interstellar community to destroy the government and military assets than causing wholesale slaughter.
So in MTU ships don’t carry nuclear weapons for use again rival or hostile nation. ...
...
... keep in mind, modern warfare design of naval vessels I’m not a big fan of 100 gun battleships.
And I'm not a fan of form over function. I see an engine on a boom as an interesting way of finding your ship and your engine on different trajectories as a result of battle damage. It's one thing to lose an engine because of a nasty hit. It's quite another to lose it because something separated you from it.
Mind you, I like your basic lines. The best way to avoid damage in any era is not to get hit in the first place. That principal sets value on agility, which - if you go by the standard Traveller assumptions - means being able to quickly spin your ship to bring your drives in line with a desired new course that the enemy hopefully hasn't anticipated. The more compact your ship, the easier it is to spin. However, the more compact your ship, the more cross-section you present to the enemy, so Broadsword-types do have certain obvious disadvantages.
Your design, on the other hand, presents a minimal cross section to the enemy - there's less to hit when you're head-on or tail-on to them. If you lose a bit in agility (which is a big if when you've got inertial dampers to help out), then your advantage in small target area more than offsets that. There's a bit more when you're broadside, but that just means your cross-section fluctuates as you maneuver, which still makes you a difficult target. You're vulnerable from above, but if you're taking fire from that angle, you're either badly outnumbered, badly outmaneuvered or you're in the kind of fleet engagement where he's taking off-angle fire as well.
Fighter planes often carry an armored crew compartment - even if the fighter doesn't survive, it pays to be able to bring the crew home to put them in another fighter. WW-I era warships often had coal bunkers strategically positioned to absorb shell hits. Modern warships - despite the overwhelming power of modern weapons - contain damage-control design features that make it more likely for the ship to stay afloat and the crew to survive even in the face of horrendous damage. Whatever the "realities" of your future weapons' power, anything you do that gives the appearance of designing the ship to maximize survival - internal airtight doors to divide halls and compartmentalize the ship, for example - makes the design look more like a purpose-built warship that expects to take damage and less like a civilian ship.
By the way, you might also consider deck hatches. I'm not sure what on that design is supposed to be the elevator, but if you lose ship's power in a serious hit, you need an alternative way to move from deck to deck while your crew effects repairs or does whatever is needed to survive until rescue arrives.